Week of the Year

What week number is it today?

Week
10
of 52 in 2026
10
Current Week
42
Weeks Left
19%
Year Complete
Today is Tuesday, March 3, 2026 - Week 10 of 2026.

Week Dates

Day Date
Sunday March 1, 2026
Monday March 2, 2026
Tuesday March 3, 2026
Wednesday March 4, 2026
Thursday March 5, 2026
Friday March 6, 2026
Saturday March 7, 2026

Frequently Asked Questions

It is currently week 10 of 2026. Our calculator updates automatically every day so you always see the current week number.

Week numbering follows ISO 8601, the international standard. Week 1 is defined as the week containing the first Thursday of the year. Weeks start on Monday in ISO convention, though some regions (like the US) start weeks on Sunday.

Yes. Most years have 52 weeks, but years that start on Thursday (or leap years starting on Wednesday) have 53 ISO weeks. This happens roughly every 5–6 years.
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Written & Reviewed by Experts
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Author

Sarah Mitchell, CPA

Certified Public Accountant • 12+ yrs payroll & workforce analytics

Specializes in time management, payroll compliance, and workforce optimization. Helped 500+ businesses streamline time-tracking.

DC
Fact-Checker

David Chen, MBA

Finance & Operations • MBA, Wharton

Specializes in financial modeling, regulatory compliance, and data accuracy verification across payroll and tax systems.

Week of the Year: The Complete Guide to ISO 8601 Week Numbering

Week numbers are one of the most widely used—yet least understood—time-tracking conventions. Businesses use them for quarterly reporting, manufacturers for production scheduling, software developers for sprint planning, and educators for academic calendars. Our Week of Year tool shows you today's week number instantly, along with a progress bar, dates for the current week, and weeks remaining in the year.

Understanding ISO 8601 Week Numbering

ISO 8601 Rule: Week 1 of a year is the week that contains the first Thursday of that year. Equivalently, it is the week containing January 4th. Weeks start on Monday and end on Sunday under ISO convention.

This means that January 1 does not always fall in Week 1. If January 1 is a Friday, Saturday, or Sunday, it belongs to the last week of the previous year (Week 52 or 53). Conversely, late December dates sometimes fall into Week 1 of the following year. This can confuse people who assume weeks always align with calendar years, but the ISO system ensures consistency for international scheduling and data exchange.

52 Weeks vs. 53 Weeks

Most years have exactly 52 ISO weeks. However, certain years have 53 weeks:

  • Years that start on Thursday (in non-leap years)
  • Years that start on Wednesday or Thursday (in leap years)
53-Week Years: Recent and upcoming 53-week years include 2004, 2009, 2015, 2020, 2026, and 2032. On average, a 53-week year occurs about once every 5.6 years.

Week Number Reference Table

Week Approximate Date Range Notable Period
Week 1Jan 1–7 (varies)New Year, goal-setting
Week 5Late JanuaryEnd of January, Q1 underway
Week 9Late FebruaryTax season begins (US)
Week 13Late MarchEnd of Q1
Week 17Late AprilUS tax deadline week
Week 22Late MayMemorial Day week (US)
Week 26Late JuneMid-year / End of Q2
Week 30Late JulyMid-summer
Week 35Late AugustBack to school
Week 39Late SeptemberEnd of Q3
Week 44Late OctoberHalloween week
Week 48Late NovemberThanksgiving week (US)
Week 52Late DecemberYear-end, holiday season

Week Numbers in Different Industries

Different sectors rely on week numbers for different purposes:

  • Manufacturing: Production scheduling, quality control tracking, and inventory cycles are organized by week number. "We produced 12,000 units in Week 34" is standard factory language. ISO weeks ensure that multinational supply chains stay synchronized.
  • Software development: Agile sprints are often mapped to ISO weeks. A 2-week sprint starting in Week 10 runs through Week 11. Release notes, bug reports, and performance metrics are frequently tagged by week number.
  • Retail and marketing: Sales campaigns, promotional calendars, and seasonal planning use week numbers to coordinate across stores, regions, and channels. "Black Friday week" is typically Week 47 or 48.
  • Healthcare: Epidemiological reporting uses CDC weeks (similar to ISO weeks) to track disease outbreaks, vaccination rates, and public health trends. "Flu peaked in Week 5" is standard CDC communication.
  • Education: Academic semesters are divided into teaching weeks. "Week 8 of the semester" tells faculty and students exactly where they are in the curriculum.

Fiscal Year Weeks

Many companies use fiscal years that don't align with the calendar year. A company with a fiscal year starting April 1 would have its "Fiscal Week 1" in early April, while the calendar shows ISO Week 13 or 14. Some retailers (like Walmart) use a 4-5-4 calendar system, where the year is divided into 13 periods of 4 or 5 weeks each, ensuring each period has the same number of weekends for comparable sales data.

Regional Differences: The ISO standard starts weeks on Monday, but the US, Canada, Japan, and several other countries traditionally start weeks on Sunday. Our calculator uses the Sunday-start convention common in the US. If you need Monday-start ISO weeks, the number may differ by one at year boundaries.

Using Week Numbers for Goal Tracking

One powerful application of week numbers is personal productivity. With 52 weeks in a year, you can set weekly targets that compound over time:

  • Read 1 book per week = 52 books per year
  • Save $50 per week = $2,600 per year
  • Exercise 3 times per week = 156 workouts per year
  • Write 1,000 words per week = 52,000 words (a novel) per year

Checking the current week number provides instant progress awareness. If you're in Week 26 and have read 20 books, you know you're 6 behind pace and can adjust accordingly.

Our Week of Year calculator updates daily, is free, and runs entirely in your browser. For related tools, see Days Left in Year, Calendar, Weeks Left in Year, and Today's Date.